Frequency Polygons and Diagrams

Defining Frequency Polygons and Diagrams

• A frequency polygon is a line graph that represents the frequencies of different categories or classes in a dataset.
• A histogram is a related type of bar graph, used for continuous data, where the bars touch each other indicating there is no gap between the classes.
• Frequency diagrams or bar charts can be used when dealing with categorical data; each category is represented by a separate bar.

Creating Frequency Polygons

• To create a frequency polygon, start by plotting the midpoint of each class along the x-axis, and its corresponding frequency along the y-axis.
• Connect each of the plotted points with straight lines.
• The frequency polygon should start and end on the x-axis.
• Frequency polygons can be drawn on the same axes to easily compare different datasets.

Interpreting Frequency Polygons and Diagrams

• The frequency is represented by the height of the point in a polygon or the height of the bar in a histogram.
• The range of the data is represented by the minimum and maximum values on the x-axis.
• Look for peaks that indicate the most occurring class in the dataset.
• Identification of outliers or unusual data is achievable through these visual representations.

Computational Techniques

• Mean, median, and mode are measures of central tendency and can be estimated from the frequency polygons.
• The interquartile range and standard deviation provide a measure of spread in the data around the mean.
• Calculation of these statistical measures helps to further analyse and interpret the data represented in the frequency polygons and diagrams.

Remember, comprehending frequency polygons and diagrams is essential for better understanding and interpretation of given statistical data. Accurate creation of these visual representations ensures proficient statistical analysis.